Combine cake mix, butter, egg and 1/3 cup evaporated milk. Mix well. Press half in greased and floured 9x13 pan. Bake 350 for 5 minutes. Sprinkle chocolate chips and nuts. Melt caramels and 1/3 cup evaporated milk over low heat. Spread over chips and nuts. Top with remaining cake mix. Bake 350 for 20 minutes. Cool.